When someone pushes a stack of many (> 10) commits to Gerrit, Zuul receives an event for each one and begins work preparing for testing of each commit. Due to <reasons that @hashar can flesh out>, the amount of prep work grows exponentially with the number of commits in the stack, which results in major delays in CI pipelines. This has been an ongoing problem, but has been especially acute in recent weeks.
Proposal: Limit the number of commits in a stack that Zuul will process. Commits beyond the limit will receive a notice that they were not processed.